The goal of this research is to provide correlative morphological and biochemical information relating to pigment organelle movement in goldfish xanthophores and melanophores. The interactions of pigment organelles with the cytoskeleton during organelle translocation will be studied in two reversible and hormone-regulated systems, xanthophores and melanophores derived from the goldfish. The translocation of melanosomes in melanophores and of carotenoid droplets in xanthophores differ in several respects which make the two cells complementary models of intracellular motility. In order to explore the nature of organelle-cytoskeleton interactions in these cells and to determine how these interactions may be altered during organelle translocation, we propose to: (i) further characterize the organelles and the cytoskeletons biochemically; (ii) describe in more detail the morphological features of organelle translocation (both ultrastructurally and in living cells) and determine, if possible, which cytoskeletal components are physically associated with the migrating pigment organelles; (iii) establish in vitro systems which support the interactions between the pigment organelles and cytoskeleton (and components thereof) and with which these interactions can be characterized; (iv) confirm the results of in vitro analyses by raising and microinjecting monoclonal antibodies against relevant organelle and cytoskeletal proteins.